/*
 * Copyright 2022 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.google.android.libraries.mobiledatadownload.file.openers;

import android.content.res.AssetFileDescriptor;
import android.os.ParcelFileDescriptor;
import com.google.android.libraries.mobiledatadownload.file.OpenContext;
import com.google.android.libraries.mobiledatadownload.file.Opener;
import java.io.IOException;

/**
 * Opener that returns an AssetFileDescriptor. Caller must close the AssetFileDescriptor when done
 * reading from it. Does not support Monitors or Transforms.
 *
 * <p>TODO: Support offset and length.
 */
public final class AssetFileDescriptorOpener implements Opener<AssetFileDescriptor> {

  private AssetFileDescriptorOpener() {}

  public static AssetFileDescriptorOpener create() {
    return new AssetFileDescriptorOpener();
  }

  @Override
  public AssetFileDescriptor open(OpenContext openContext) throws IOException {
    ParcelFileDescriptorOpener pfdOpener = ParcelFileDescriptorOpener.create();
    ParcelFileDescriptor pfd = pfdOpener.open(openContext);
    // TODO(b/115933017): consider wrapping the AFD to force it to implement Closeable on all sdks
    return new AssetFileDescriptor(pfd, 0, pfd.getStatSize());
  }
}
